Improved compile warnings check; the --enable-compile-warnings parameter

2000-12-01  Martin Baulig  <baulig@suse.de>

	* compile-warnings.m4: Improved compile warnings check; the
	--enable-compile-warnings parameter now takes 5 different
	values (no/minimum/yes/maximum/error). AC_SUBST(WARN_CFLAGS).

svn path=/trunk/; revision=1475

2 files changed, 81 insertions, 41 deletions

diff --git a/macros2/ChangeLog b/macros2/ChangeLog
index 1d6022c..91fc618 100644
--- a/macros2/ChangeLog
+++ b/macros2/ChangeLog
@@ -1,3 +1,9 @@
+2000-12-01  Martin Baulig  <baulig@suse.de>
+
+	* compile-warnings.m4: Improved compile warnings check; the
+	--enable-compile-warnings parameter now takes 5 different
+	values (no/minimum/yes/maximum/error). AC_SUBST(WARN_CFLAGS).
+
 2000-11-29  Martin Baulig  <baulig@suse.de>
 
 	* gnome.m4, gnome-gnorba-check.m4, gnome-fileutils.m4: Removed.
diff --git a/macros2/compiler-flags.m4 b/macros2/compiler-flags.m4
index 63f8e2e..7294784 100644
--- a/macros2/compiler-flags.m4
+++ b/macros2/compiler-flags.m4
@@ -2,56 +2,90 @@ dnl GNOME_COMPILE_WARNINGS
 dnl Turn on many useful compiler warnings
 dnl For now, only works on GCC
 AC_DEFUN([GNOME_COMPILE_WARNINGS],[
-  AC_ARG_ENABLE(compile-warnings, 
-    [  --enable-compile-warnings=[no/minimum/yes]	Turn on compiler warnings.],,enable_compile_warnings=minimum)
+    dnl ******************************
+    dnl More compiler warnings
+    dnl ******************************
 
-  AC_MSG_CHECKING(what warning flags to pass to the C compiler)
-  warnCFLAGS=
-  if test "x$GCC" != xyes; then
-    enable_compile_warnings=no
-  fi
+    if test -z "$1" ; then
+	default_compile_warnings=no
+    else
+	default_compile_warnings="$1"
+    fi
 
-  if test "x$enable_compile_warnings" != "xno"; then
-    if test "x$GCC" = "xyes"; then
-      case " $CFLAGS " in
-      *[\ \	]-Wall[\ \	]*) ;;
-      *) warnCFLAGS="-Wall -Wunused" ;;
-      esac
+    AC_ARG_ENABLE(compile-warnings, 
+    [  --enable-compile-warnings=[no/minimum/yes/maximum/error]	Turn on compiler warnings.], [enable_compile_warnings="$enableval"],[enable_compile_warnings="$default_compile_warnings"])
 
-      ## -W is not all that useful.  And it cannot be controlled
-      ## with individual -Wno-xxx flags, unlike -Wall
-      if test "x$enable_compile_warnings" = "xyes"; then
-	warnCFLAGS="$warnCFLAGS -Wmissing-prototypes -Wmissing-declarations"
-      fi
+    warnCFLAGS=
+    if test "x$GCC" != xyes; then
+	enable_compile_warnings=no
     fi
-  fi
-  AC_MSG_RESULT($warnCFLAGS)
 
-  AC_ARG_ENABLE(iso-c,
+    warning_flags=
+    realsave_CFLAGS="$CFLAGS"
+
+    case "$enable_compile_warnings" in
+    no)
+	warning_flags=
+	;;
+    minimum)
+	warning_flags="-Wall -Wunused"
+	;;
+    yes)
+	warning_flags="-Wall -Wunused -Wmissing-prototypes -Wmissing-declarations"
+	;;
+    maximum|error)
+	warning_flags="-Wall -Wunused -Wchar-subscripts -Wmissing-declarations -Wmissing-prototypes -Wnested-externs -Wpointer-arith"
+	CFLAGS="$warning_flags $CFLAGS"
+	for option in -Wsign-promo -Wno-sign-compare; do
+		SAVE_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS $option"
+		AC_MSG_CHECKING([whether gcc understands $option])
+		AC_TRY_COMPILE([], [],
+			has_option=yes,
+			has_option=no,)
+		CFLAGS="$SAVE_CFLAGS"
+		AC_MSG_RESULT($has_option)
+		if test $has_option = yes; then
+		  warning_flags="$warning_flags $option"
+		fi
+		unset has_option
+		unset SAVE_CFLAGS
+	done
+	unset option
+	if test "$enable_compile_warnings" = "error" ; then
+	    warning_flags="$warning_flags -Werror"
+	fi
+	;;
+    *)
+	AC_MSG_ERROR(Unknown argument '$enable_compile_warnings' to --enable-compile-warnings)
+	;;
+    esac
+    CFLAGS="$realsave_CFLAGS"
+    AC_MSG_CHECKING(what warning flags to pass to the C compiler)
+    AC_MSG_RESULT($warning_flags)
+
+    AC_ARG_ENABLE(iso-c,
     [  --enable-iso-c          Try to warn if code is not ISO C ],,
     enable_iso_c=no)
 
-  AC_MSG_CHECKING(what language compliance flags to pass to the C compiler)
-  complCFLAGS=
-  if test "x$enable_iso_c" != "xno"; then
-    if test "x$GCC" = "xyes"; then
-      case " $CFLAGS " in
-      *[\ \	]-ansi[\ \	]*) ;;
-      *) complCFLAGS="$complCFLAGS -ansi" ;;
-      esac
-
-      case " $CFLAGS " in
-      *[\ \	]-pedantic[\ \	]*) ;;
-      *) complCFLAGS="$complCFLAGS -pedantic" ;;
-      esac
+    AC_MSG_CHECKING(what language compliance flags to pass to the C compiler)
+    complCFLAGS=
+    if test "x$enable_iso_c" != "xno"; then
+	if test "x$GCC" = "xyes"; then
+	case " $CFLAGS " in
+	    *[\ \	]-ansi[\ \	]*) ;;
+	    *) complCFLAGS="$complCFLAGS -ansi" ;;
+	esac
+	case " $CFLAGS " in
+	    *[\ \	]-pedantic[\ \	]*) ;;
+	    *) complCFLAGS="$complCFLAGS -pedantic" ;;
+	esac
+	fi
     fi
-  fi
-  AC_MSG_RESULT($complCFLAGS)
-  if test "x$cflags_set" != "xyes"; then
-    CFLAGS="$CFLAGS $warnCFLAGS $complCFLAGS"
-    cflags_set=yes
-    AC_SUBST(cflags_set)
-  fi
+    AC_MSG_RESULT($complCFLAGS)
+
+    WARN_CFLAGS="$warning_flags $complCFLAGS"
+    AC_SUBST(WARN_CFLAGS)
 ])
 
 dnl For C++, do basically the same thing.